Manufacture of footwear



proved character.

Patented Dec. 8, 1931 UNITED STATES FRED N. BECKWITH, F BROOKLIN'E, MASSACHUSETTS MANUFACTURE OF FOOTWEAR No Drawing.

This invention pertains to the manufacture of footwear, and relates more particularly to a process or method of stiffening certain parts of a shoe, for example the heel or toe portion of the shoe upper, and to a stiffener of im While in its broader aspects, the invention is of wider application, I shall hereinafter make more specific reference to its utilitywith reference to stiffeners for the forward ends of shoes, commonly known as box-toe stiffeners, toe boxes, etc. Such stiffeners are intended to assist the upper leather, or other upper material at the forward part of the shoe, in maintaining its lasted shape after the last is withdrawn, and-for this purpose should be as stiff, strong, resilient, and shape-retaining in the finished shoe as possible, while on the other hand, during the process of lasting, a stiffener must be so soft and pliable as to permit it to be drawn snugly about the last.

Stiffeners having different characteristics, 1 as respects the rapidity and degree of hardening after lasting, are required in the manufacture of shoes of different types. Thus in making McKay shoes it is desirable to have the stiffener become very hard as quickly as possible after lasting, in order to avoid delay in the last-pulling operation. On the other 30 hand, in making Goodyear welts, the shoes are allowed to stand or mull for a considerable period of time after lasting, in order that the shoe parts may become set in final shape, and in this case it is desirablethat the stiffener harden gradually as the mulling process proceeds. Furthermore, in making turn shoes, the stiffener must remain soft and pliable until after the turning process, and because other prior forms of stiffener have failed to meet this requirement, turn-shoe manufacturers have, in most cases, been obliged to content themselves with stiffeners consisting merely of lightly treated cloth, leather, or the like, of sufficient thickness to impart some degree of stiffness when dry to the toe of the shoe.

With the object of improving the quality of footwear, and simplifying and reducing the cost of manufacture, the present invention provides a novel process of stiffening the shoe Application filed April 17,

1930. Serial No. 445,213.

upper and an improved stiffener of universal applicability, that is to say, a stiffener which may be used with complete satisfaction in any of the usual types of'shoe, including turn shoes, so that it will no longer be necessary for the shoe manufacturer who makes several types of shoe to keep two or more types of stiffener in stock.

Various kinds of stiffener have been proposed from time to time for use in one or another kind of shoes, but prior to the present invention, so far as is known to me, no satisfactory stiffener of universal applicability has been produced. One common form of stiffener consists of close, firmly woven textile fabric impregnated with paste, which is softened (immediately before use by the shoe manufacturer) by immersing it in water. While this type of stiffener is thus readily softened for lasting, and becomes hard and stiff again when dry, it has certain disadvantages. For instance, it softens readily from the effects of foot moisture, or wetting of the shoe during wear, and immediately loses its shape; its impregnant paste exudes when it is wet preparatory to lasting, and is irregularly scraped off by the lasting wipers, gumming up the latter and leaving the stiffener irregularly coated, so that it is of nonuniform stiffness when dry; and the pasty so coating of such a stiffener takes up a large amount of water which tends to stain the lining and upper leather and which makes the stiffener slow to dry, so that the last can not be pulled as soon as desired, and to obtain the necessary stiffness, it is necessary to use from two to five plies of a closely woven and expensive fabric.

Another type of stiffener, commonly used, makesuse of a cellul ose derivative, for ex- 9O ample cellulose nitrate or acetate as the stiffening agent, either applied to a fabric base or in sheet form, for example celluloid, but this necessitates the use of acetone or other highly volatile and inflammable solvent for 9 5 softening the stiffener preparatory to lasting, and this'is objectionable by reason of the fire hazard involved and its tendency to cause staining.

Still another type of stiffener employs some v7 thermoplastic agent, as for example a normally hard gum which softens when heated. These stiffeners must be softened by the use of heat; they must be lasted while still hot; and they immediately stiflen when they cool. These thermoplastic stifi'eners usually comprise a felt base which is considered necessary to absorb the requisite amount of binder, but such a base is not of. the requisite strength to withstand the lasting strains, and thermoplastic stiffen'ers harden much too quickly for use in turn shoes. I

As contrasted with these prior stiffeners, the material which I employ preferably comprises any suitable strong base, for example one or more plies of textile fabric which for the purpose need not be of fine or close weave,

'a plain coarse buckram being adapted for the purpose. This base, which thus may be of relatively cheap material, as compared with the material commonly employed in making which is normally soluble or extensible in paste-stiffened toe boxes, is coated (or preferably isimpregnated) in any desired manner with a stiffening substance, usually colloidal in its nature (for example glue) water but which after treatment with a suitable reagent (also preferably water soluble) becomes, after subsequent drying, substantially impervious to the action of water or at least does not again soften readily when exposed to moisture. I contemplate that a substantial number of such stiffening materials and corresponding reagents may be employed. Among such stiffening materials useful in greater or less degree for the purpose may be mentioned solub'le gums, gelatine,

pectin, Ir1sh moss, alginates, or combinatlons thereof, all of which materials fall within the general class of hydrophilic colloids which are water dispersible to give a soft or liquid phase and which are normally reversible, that is to say, change from soft (or liquid) to hard (or:solid) phase, or vice versa, in accordance with the proportion of dispersing medium present. Usually water will be the predominant ingredient in the dispersing medium employed, but under some circumstances other ingredients may be used, for' example acids or alkalis in greater or lesser proportion to the water. While I apprehend that most stiffening materials useful for the purpos must be of colloidal character, I contemplate the use of any stiffening substance which, in response to the amount of wateralo-- sorbed by it, changes from solid to liquid phase or vice versa, thus forming a normally reversible system. y

In order to cause such a reversible system, whether colloidal or otherwise to become irreversible while in its dry or solid phase,

/ I combine with it a suitable reagent, hereinafter for-convenience termed the hardener hardening agent with the understanding that these terms are employed with more par- 'most cases the colloid, after treatment with the hardener, is in fact of somewhat increased physical hardness as compared with the untreated oolloid.

When glue, for example, is used as the stiffening material, I find that formaldehyde in aqueous solution gives good results, causing the glue to becomeverystifi, hard and waterresistant when dry. Other hardening agents,

for example chrome alum, bichromate of potash, tannic acid, etc. may be employed, and I note. that most such reagents'contain an acid radical which I apprehend causes the colloidal stiffening material to become resistant to water softening or dispersion. Such hardening agents appear in general to fall within the class referred to as astringents in pharmaceutical nomenclature.

While the selected stiffening material alone may be applied to the base fabric, for examplc to cotton cloth, I prefer to combine with. it a suitable, substantially inert, but preferably water-absorbent, filler, for example, an inorganic powder such as oxide of magnesia, or chalk, and in order to insure rapid penetration of the hardening agent into the completed stiffener (and incidentally to control the ultimate stiffness and hardness .of the stiffener) I prefer to combine a small percentage of glycerine glucose, dextrose, etc., With the stiffener and filler before applying the treating substance to the fabric. The glycerine, through-its hygroscopic character or natural attraction for moisture, makes the stiffener, so to speak, thirsty, so that when the stifiener is immersed in a water solution of the hardening agent, the latter is absorbed very rapidly into the innermost parts of the stiffener. Usually, the treating substance comprises a stiffening material, e. g. glue, and other ingredients which have little if any stiffening action, and I contemplate that the treating substance may comprise more than one stiffening material, or materials which in combination have a stiffening action and that the expression stiffening materia as here used may be inclusive of any or all of the ingredients of the treating substance.

-While some of the advantages of the invention may be obtained by coating the base fabric, as by brushingor' immersing in the treating substance, I prefer to cause the substance to enter into the interstices of the fabric-and of its constituent yarns and fibers by pressure, either mechanical or pneumatic, as for example by passing the material beproximately 100 parts by weight of tween heavy rolls in a bath of the treating glue, and 225 parts of water giving a suitable strength) and when the glue has been softened and thoroughly dispersed, I add 5 parts of glycerine more or less and 2 parts by weight of powdered magnesium oxide. The several ingredients are thoroughly incorporated, and the treating substance thus formed is applied to the cloth,(desirably by pressure) as suggested. The treated cloth is now permitted to dry and ifdesired, two or more plies of the cloth may be combined, either before or after treatment, although for many purposes, a single Ely of the treated material 'is sufiicient. lternatively, instead of using a fabric base, it is possible to form the treatingsubstance, with or without the incorporation of unwove'n fibrous materials, into sheets, which when dry, may be used in the same way as the impregnated cloth described. R

The prepared sheet material with its incorporated stiflener in its dry, hard or solid phase may now be delivered directly to the shoe manufacturer to be cut by .him into pieces of the proper size and shape, orit may be cut into stlfieners by the maker, and sold to the shoe manufacturer in this form. These stifl'eners may be skived or subjected to any other usual preliminary treatment.

Immediately before in an aqueous solution of the selected hardener, for example a 20 per cent solution of formaldehyde. Aftg remaining in the solution for a suitable length of time (that is until soft enough for lasting), the softened stiffener may be applied directly to the shoe to be lasted, but preferably the stiffener is withdrawn from the solvent and allowed to mull until the solvent is distributed with substantial uniformity throughout the thickness of the stiffener. During the softening process, the stiffener swells somewhat, but the lmpregnant material shows little if any tendency to exude, even under the pressure and scraping action of the lasting wipers. After assembly of the prepared stifl'ener with the other parts forming the toe portion of the upper, the shoe is lasted. B using a hardening solution of properly adjusted strength or character; the time of reaction maybe regulated, and since the treating medium does the lasting process,- the stifi'eners are wet, preferably by dipping,

not exude and does not take up an excess of water gas do usual water-softened stifi'eners) the sti ener dries rapidly without tendency to stain adjacent shoeparts. The hardener makes the stiffening material irreversible, and thus afterdrying in the lasted shoe, the stiffener is but slightly aflected thereafter by the action of moisture or even by actual wetting so that it retains its shape throughout the life of the shoe. Even after prolonged soaking such a stiffener retains'sufiicient resiliency to support the shoe upper in proper shape, whereas an ordinary paste impregnated stiffener which has not been subjected to hardening, becomes soft, flabby and nonresilient when subjected to even a small amount of moisture. v

Since the rapidity of hardening and the degree of stiffness depends largely upon the strength and kind of hardener used, the

present invention makes it possible to. em-

ploy the same kind of stiffener in making shoes of all types, even making it possible to provide a turn shoe with a thin and light water-softened stiffener, which becomes permanently hard, stiff and resilient after turning, which to my knowledge has never before been accomplished.

While in general I prefer to proceed as above suggested I may, under some circumstances prefer to combine the hardener directly with the stiffening material in making up the stiffener for delivery to the shoe manufacturer, but in such a case it is evident that the hardener used must react withthe stiffening agent only after the stiffener has been lasted. One way of attaining this result is to apply the hardener to the previously impregnated and dry stiffener in the form of a dry powder which may be combined with the stiffener under pressure. Then when the stiffener is subsequently moistened with water, the hardener reacts with the stiffening material in the same way as above described to make the latter irreversible, and the shoe manufacturer is not put to the trouble of making 11 the hardening solution.

It is to be noted that the stiffener repared as above described by impregnated c 0th with glue, magnesia, and glycerine', or equivalent ingredients and allowing it to dry is substantially stronger than usual water-softened stifl'ener so that the impregnated fabric may be cut into stiffener blanks without reference to the direction of its constituent. threads. This results in a substantial saving in material, since in making prior water-softening stiffeners it has been necessary to exercise care in laying out the blank upon the material so as to have the warp and weft threads of the fabric run in the proper direction to 1 comprises as steps cuttin Ill silient for a given thickness and weight of material than any prior water-softened stifl'- ener known to me, and thus may be used to advantage in turn shoes, for example, by

softening the stiflener in lain water without the use of a hardener. Ar ter association with the other shoe parts and lasting, this stiifener affords greater strength and stifi'ness to the shoe parts when dry than ordinary stiil'eners of heavierandmore expensive type and if no hardener is employed, the turning of the shoe may be delayed as long as desired.

The stifi'ener thus provided, being of universal applicability, is su hcient to meet the requirements of manufacturers of all types of shoes, it being merely necessary for the shoe manufacturer to prepare a hardening solution of the requisite strength to provide the desired degree of hardness and the proper rate of hardening. Since no heat is required in softening and since the softening solution is not inflammable, the process is greatly simplified and the diliiculty and cost of applying the stideners to the shoes are substantially reduced.

I claim:

1. That process of making shoes which comprises as steps cutting a blank of a shape and size appropriate to form a shoe stiii'ener from a piece of dry material impregnated with a water dispersible liquid-phase normally reversible stiflening materialfmoistening the blank with an aqueous reagent solution which reduces the stiflening material to its liquid phase but which upon subsequent drying, makes it substantially irreversible, incorporating the blank while wet in a shoe upper, lasting the shoe while the blank is still wet, and allowing the blank to dry and resume its normal stillness.

2. That process of making shoes which or a blank of a shape and size appropriate to 8m a shoe stifi'ener. from a piece of fabric having in its interstices a water dispersible liquid phase normally rev ersible colloid in solid condition, moistening the blank with an aqueous reagent which reduces the solid colloid to its liquid phase and which makes it irreversible upon subsequent drying, incorporating the blank while wet in a shoe upper, and lasting the shoe while the blank is still wet.

3. That process of. making shoes which comprises as steps preparing a stifiener member comprising stiffening material which when dry is hard, tough, and resilient, but

- which when wet with water normally becomes soft and pliable, wetting the stiffener with an a ueous solution of a hardening reagent to so ten it, assembling the soft and plastic stifiener with other parts of the shoe, lasting the shoe, and allowing the stiffener to dry and become permanently still and hard. I

4. That process of making shoes which comprises as steps preparing a stifiener conmenses taining a stiffening ingredient which normally softens as often as it is wet with water but which again becomes hard, stifi and resilient when dry, dipping the dry stifiener in a watersolution of a hardening reagent, associating the stidener with other parts of an unlasted shoe, lasting theshoe and allowing it to dry. I

5. That process of making shoes which comprises as steps preparing a stifiener containing a dry gelatinous substance which normally softens as'often as it is wet but which when dry is hard and stifi, wetting the stiflener to soften it in a solution containing a reagent adapted to react with the gelatinous substance to make the latter, after drying,

resistant to softening by water, vassociating the stifl'ener with unlasted shoe parts, lasting the shoe, and allowing it to dry.

6. That process of making shoes which comprises as steps preparing a stifl'ener member comprising stiffening material which when dry is hard, tough, and'resilient, but which when wet with waternormally becomes soft and pliable, wetting such stifiener, assembling the wet and pliable stifiener with other parts of the shoe upper, and lasting the shoe and permitting the stiflener to dry while allowing the stifiener material to react with a reagent which makes it resistant to softening when subsequently subjected to moisture' 7. That process of makingshoes which comprises as steps preparing a stifiener containing a dry organic stifiening ingredient which normally softens as often as it is subjected to water but which becomes hard, stifi and resilient when dry, softening the Std?- ener by wetting it. with a water solution of which when dry is hard, tough and resilient,

but which when wet with water normally becomes soft and pliable, dipping the stillener in an aqueous solution of a hardening reagent, permitting the stiffener to mull until the solution is distributed with substantial uniformitythroughout the substance of the stiffener, assembling the stiflener with lother shoe parts, lasting the shoe, and permitting the stiffener to dry.

9. That process of ma comprises as steps preparing a stifiener member consisting of a base fabric impregnated with a treating medium comprising a filler, a hygroscopic substance, and stiffening material which, when dry, is hard and resilient,

' but which when wet normally becomes soft mg shoes which and pliable, wetting such stiffener to make it pliable with an aqueous solution of a hardening reagent, 'assembling'the soft and pliable stiflener with other shoe parts, lasting the shoe, and permitting the stiffener to dry.

10. That process of making shoes which comprises as steps preparing a stiffener containing dry glue, softening the stiffener by wetting it with a water solution of formaldehyde, associating the stiffener with other parts of an unlasted shoe, lasting the shoe, and allowing the stiffener to dry.

11. A lasted shoe comprising in its upper a shaped stiffener comprising gelatinous stiffening material, an inert water absorbent filler, and a hygroscopic substance.

g 12. A lasted shoe stiffener which is hard,

dry and resilient and comprises a textile base fabric impregnated with a treating substance including glue, oxide of magnesia, and glycerine.

13. A lasted shoe comprising a box toe stiffener consisting of textile fabric-impregnated with glue treated with formaldehyde to make it resistant to the action of water.

14. A lasted shoe comprising a stiffener consisting of woven fabric impregnated with a' mixture .of glycerine, an inert water ab sdrbent filler, and glue treated with formaldehyde.

15. Allard, dry, and resilient shoe stiffener comprislng cloth impregnated with a treat ing substance including an inert filler, a hy groscopic material, and stiffening material wh ch is normally capable of repeated reversal between solid and liquid phases in response to changing moisture conditions, said stiffener material being combined with a reagent which prevents return of the stiffening material to the liquid phase.

16. A stiffener blank ready for insertion in an unlasted shoe upper and consisting of a fabric blank of a size and shape appropriate for use in stiffening a predetermined part of the upper, said stiffener blank comprising stiffemng material normally capable of 'repeated reversal between hard and soft phase in response to varying moisture conditions, sa d stiffen ng material, in the hard phase, being tough, strong and resilient, but being in its soft phase when the stiffener is ready for incorporation in the shoe, and a reagent associated with the stiffening material which reacts with the latter so that, after incorporation in the shoe and resumption of its hard I phase, the stiffening material will not resume its soft phase upon subsequent exposure to moisture.

I; 17. A shoe stiffener ready for insertion h in a shoe upper, said stiffener being of appropriate shape and size for insertion in the unlasted upper and comprising a colloidal stiffenjng material normally capable of repeated reversal between solid and liquid phase in response to varying moisture conditions, said material being in the liquid phase when the stiffener is ready for insertion in a shoe, and a reagent combined with said colloidal material which reacts with such material so that, after incorporation in a shoe and resumption of its solid phase, the stiffening material will not resume its liquid phase upon subsequent exposure to moisture.

18. A shoe stiffener ready for insertion in a shoe upper, said stiffener consisting of a blank of sheet material of a size and shape appropriate for insertion in the unlasted upper and comprising gelatinous stiffening material normally-capable of repeated reversal between hard and soft phase in response to varying moisture conditions, said material being in the soft phase when the stiffener is ready for insertion in a. shoe, and a reagent capable of reacting with the stiffening material so that after incorporation in the shoe and resumption of its hard phase, the stiffening material will not resume its soft phase upon subsequent exposure to moisture.

19. A shoe upper prepared for lasting having assembled therewith a toe stiffener blank, said blank comprising woven textile fabric treated with glue which is normally capable of reversal between hard and soft phases in response to varying moisture conditions, said glue being in the soft phase when the stiffener is assembled with the upper, and a formaldehyde combined with the glue WhlCh causes the latter, after incorporation in a shoe and resumption of its solid phase, to become resistant to the action,of moisture.

20. A shoe stiffener comprising sheet material impregnated with a mixture comprising substantially five pants of glycerine, two parts of oxide of magnesia and 100 parts of lue. g Signed by me at Boston, this 16th day of April, 1930.

FRED N. BECKWITH.

Massachusetts, 

